Mold centering device



Nov. 13, 1962 T. H. OWEN MOLD CENTERING DEVICE Filed April 21, 1960 /J-;VJENT0R. THOMAS H. OWEN BY W (742% ATTQRNEY United States PatentOfiice 3,%3,ll2 Patented Nov. 13, 3.962

3,te63,112 MGM) CENTERiN-G DEVICE Thomas H. Gwen, Benton Harbor, Mich, assignor to Clark Equipment Company, a corporation of Michigan Filed Apr. 21, teen, Set. No. 23ers 4 Claims. or. 222-453 My invention relates to locating devices, and more specifically to locating devices for elements or parts of machines or manufactured products in which certain connected elements undergo different degrees of expansion under some conditions of operation.

For example, in a foundry machine for casting metal parts, comprising a circular die mounted in concentric relation on a base plate with a core member located in concentric relation inside the cavity formed by the die and base plate, it is very important that the die, base plate and core member are maintained in concentric relationship during the casting process because if this relationship is not maintained the casting will be imperfect.

In a typical case the core member and base plate can be held in concentric relation by the use of a centering dowel. However, the die and base plate must also be kept concentric; and this presents a problem because the die and base plate may expand ditierent amounts during the casting process, so any locating means must allow for difierent degrees of expansion between the die and base plate. It is this problem which my invention solves through a pin and slot arrangement which keeps the die and base plate concentric while allowing them to expand or contract different amounts and even to expand or contract non-uniformly.

The main object of my invention is to provide a simple and easy to fabricate structure for keeping connected machine elements concentric although they undergo different degrees of or non-uniform expansion or contraction.

In carrying out my invention in one preferred form thereof, I provide an upper machine element with four downwardly projecting round pins. Two of these pins are located on either side of the center on one horizontal axis through the center of the machine element. The other two pins are located on opposite sides of the center on another horizontal axis through the center of the machine element at right angles to the first axis. A lower machine element to be connected to the first or upper machine element has four radially extending slots mating respectively with the four pins. The pair of pins and mating slots on one axis holds that axis on the center at all times regardless of expansion of one or both machine elements on either side of the axis. The other pair of pins and slots holds the second axis on the center also regardless of expansion or retraction of either or both of the connected elements. Inasmuch as the two horizontal axes are held so that they always coincide with the center or vertical axis the two machine elements are at all times held concentric with each other.

For a clearer and more complete understanding of my invention reference should be had to the accompanying drawing in which FIGURE 1 is a schematic representation in vertical section of a foundry machine embodying my invention, while FIGURE 2 is a bottom view of the machine of FIG URE 1.

In the drawing numeral It? represents a die or upper mold member of a foundry or casting machine which may be used for casting circular parts of metal. The complete machine is represented generally by the numeral 11. The numeral 34 designates the base plate or lower mold member of the casting machine 11 which cooperates with the upper mold member to form a cavity 13. A core member 48 of known type may be located within the cavity 13 to provide the cast or molded part with the desired configuration.

The upper mold member 10 has a pair of downwardly extending pins 12 and 14 projecting from it intermediate its perimeter and its center which is indicated by the vertical axis 16. A line passing through the centers of pins 12 and 14 defines a horizontal axis 18 which passes through center 16 of the die 10. The die 10 also has another pair of downwardly extending pins 20 and 22 projecting from it intermediate its outer edge and its center 16. A line passing through the centers of pins 29 and 22 defines a second horizontal axis 24 at right angles to the first horizontal axis 18 which intersects axis 18 at center axis 16.

The pinsv 12, 14, 2t) and 22 mate respectively with radially disposed slotted bushings 26, 28, 30 and 32 set in the base plate or lower mold member 34 intermediate its outer edge and vertical axis 16 which also indicates the center of member 34. The slots 36, 38, 40 and 42 in said slotted bushings 26, 28, 30 and 32 are positioned so they extend radially outwardly from the center 16 along the respective axes. The fit between the pins 12, 14, 2t and 22 and slots 36, 38, 4t} and 42 is such that no significant lateral movement of the pins with respect to their respective axes is allowed, yet the pins will not bind in the slots due to expansion when heated.

As shown, the base plate 34 has a central opening receiving a centering dowel 44 which holds core member 48 centered on the base plate 34.

In operation, when the die 10 and the base plate 34 are brought together, the pins 12, 14, 20 and 22 fit into slots 36, 38, 4t and 42 of the corresponding slotted bushings 26, 28, 3t and 32. The pins 12 and 14 in their slots 36 and 33 hold the axis 18 always on the center 16 regardless of any difference in expansion and contraction of the upper mold member It? and the lower mold member 34. Similarly, the pins 21} and 22 in their slots 40 and 42 always hold the axis 24 on the center 16 regardless of any difference in expansion or contraction of the upper and lower mold members. Thus, since the two axes always coincide with the center axis 116 the upper and lower mold members remain concentric at all times. It will be appreciated that the pins may move inwardly and outwardly somewhat relative to their respective slots but that there can be no lateral movement of the pins relative to the slots, thus both horizontal axes are held on center as indicated.

While I have shown and illustrated herein a form of the invention in which the pins and slots are all equi-distant from the center, it will be appreciated that the invention is not limited to such an arrangement. The pins and their respective slots can be at varying distances from the center as long as they are on the respective axes. Also, whilethe foregoing specification and the following claims make reference to horizontal and vertical axes as shown on the drawing, it will be readily appreciated that the positions of the respective axes with respect to vertical and horizontal is not critical and that their designation as vertical and horizontal axes is for convenience in distinguishing them from each other but that the invention is not limited to the center axis being vertical or the other axes being horizontal.

Thus, while I have shown and described herein a preferred embodiment of my invention, it will be readily understood by those skilled in the art that modifications may be made in my invention, and I intend to cover by the appended claims all such modifications falling within the true spirit and scope of the invention.

I claim:

1. In combination, an upper mold member, four downwardly extending substantially equally spaced pins attached to said upper mold member intermediate its perimeter and center, a lower mold member, a core member, a centering dowel which holds said core member in fixed relationship to said lower mold member, a cavity defined by said upper mold member, core member and lower mold member, four bushings positioned in said lower mold member, and four radially extending slots in said bushings which slidably receive said pins.

2. In combination, an upper mold member, a lower mold member, a pair of longitudinally extending pins connected to said upper mold member in such a manner that a line through their centers intersects the longitudinal axis of said upper mold member, a pair of slotted bushings positioned in said lower mold member, a pair of radially extending slots in said slotted bushings which receive said pins in such a manner as to allow negligible lateral movement yet not becoming bound due to expansion when heated, a second pair of pins connected to said upper mold member in such a manner that a line through their centers intersects the longitudinal axis of said upper mold member at right angles to the abovementioned line, a second pair of slotted bushings positioned in said lower mold member, a second pair of radially extending slots in said second-mentioned slotted bushings which receive said second-mentioned pins in such a manner as to allow negligible lateral movement yet not become bound due to expansion when heated, a core member, a centering dowel which holds said core member in fixed relationship to said lower mold member and a cavity defined by said upper mold member, core member and lower mold member.

3. In combination, a first mold member having a first flat surface thereon adapted to engage another mold member and an axis normal to the said surface, four substantially equally spaced axially extending pins projecting from the said surface, the said pins being approximately equidistant from the said axis, a second mold member having a second flat surface adapted to abut the said flat surface of the first mold member, a core member, means for holding the said core member in fixed relationship on one of the said members whereby a cavity is defined by the said mold members and the said core member when the said two fiat surfaces are in abutting relation, and four radially extending slots in the said second flat surface adapted to slidably receive the said pins, the said slots permitting radial movement of the said pins relative to the said second surface but preventing lateral movement between such pins and the respective adjacent portions of the second surface.

4. In combination, a first mold member having a planar surface adapted to abut another mold member and an axis normal to the said planar surface, four axially extending pins projecting from the said planar surface, two of the said pins lying on a second axis which is parallel to the said planar surface and intersecting the said first axis, the other two pins lying on a third axis which is parallel to the said planar surface and intersecting both the said first and second axes at the junction thereof and forming a right angle with the second axis, a second mold member having a planar surface adapted to abut the said planar surface of the first mold member, a core member, means for holding the said core member in fixed relationship with one of the said mold members whereby a cavity is defined by the said mold members and the said core member when the said planar surfaces are in abutting relation, and four radially extending slots in the said planar surface on the second mold member arranged to receive the said pins when the said planar surfaces are in abutting relation, the said slots permitting radial movement of the said pins relative to their respective slots but preventing lateral movement between the pins and their respective slots.

References Cited in the file of this patent UNITED STATES PATENTS 2,668,336 Jones Feb. 9, 1954 OTHER REFERENCES The Foundry, pp. 92, 94, 95, 96, August 1950. Bakelite Phenolic Resins, copyright 1950 by Union Carbide & Carbon Corp., 15 pp.

UNITED STATES PATENT OFFICE CERTIFICATE. OF CORRECTION Patent No. 3,063,112 November 13, 1962 Thomas H Owen It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 1, after "said" insert mold Signed and sealed this 23rd day of April 1963.,

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents 

